The prevalence of major depressive disorder (MDD) among adolescents has been rising steadily, making it a serious public health issue that affects young people's psychological well-being and social functioning. Although traditional treatments such as pharmacotherapy and psychotherapy have demonstrated certain efficacy, they are often limited by delayed onset of action, poor adherence, and potential side effects. In recent years, transcranial alternating current stimulation (tACS), a novel non-invasive neuromodulation technique, has shown promising progress in the treatment of adult depressive disorders. This review summarizes the potential applications of tACS in adolescent MDD, with a focus on its clinical evidence and parameter mechanisms. Building on findings and insights from adult studies, it further proposes future research directions, aiming to provide new theoretical and practical perspectives for the intervention of adolescent depressive disorders.